Journal article
Electron-Mediated Transport in Space, Astrophysical, and Laboratory Plasmas
Space science reviews, Vol.222(7), 75
10/05/2026
DOI: 10.1007/s11214-026-01328-0
PMCID: PMC13638725
PMID: 42840283
Abstract
Electron-mediated transport is fundamental to the thermal and dynamical evolution of plasmas across a vast range of physical environments, from the solar wind and solar atmosphere to astrophysical systems such as galaxy clusters and accretion flows, to laboratory and fusion plasmas. This article reviews the current state of understanding of electron transport, drawing together observations, simulations, and theory to contextualise key challenges and open questions. We characterise plasma environments using the Knudsen number and electron beta, and highlight that some systems fall in an intermediate regime between the collisional and collisionless limits. In the collisional limit, transport is well described by the Chapman-Enskog-Braginskii framework, yielding anisotropic heat fluxes and momentum transfer rates governed by the ratio of the electron mean free path to the electron gyroradius. In the collisionless limit, Landau-fluid closures and quasilinear wave-particle interaction theory describe heat flux regulation through resonant instabilities, particularly whistler-mode waves, which suppress parallel electron heat flux below Spitzer-Härm predictions in high-beta plasmas. We review approaches to bridging collisional and collisionless regimes, including velocity-space-dependent collision operators, moment-based interpolating closures, and data-driven methods trained on fully kinetic simulations. Comparison with solar wind observations from the Parker Solar Probe and Wind missions reveals that the current attempts at bridging collisional and collisionless closures account for only limited regions of parameter space, underscoring the need for improved models. Four central challenges are identified for future transport theory: capturing the velocity-space dependence of collisional and collisionless scattering, describing spatial transitions between transport regimes, incorporating turbulence, and developing computationally tractable effective collision operators for large-scale simulations.
Details
- Title: Subtitle
- Electron-Mediated Transport in Space, Astrophysical, and Laboratory Plasmas
- Creators
- Jesse T Coburn - Centre National de la Recherche ScientifiqueMaria Elena Innocenti - Ruhr University BochumDaniel Verscharen - University College LondonAnton Artemyev - University of California, Los AngelesJasper Halekas - University of IowaWence Jiang - National Space Science CenterMatthew W Kunz - Princeton UniversityM J Pueschel - Centre National de la Recherche ScientifiqueMario Riquelme - University of ChileŠtěpán Štverák - Czech Academy of Sciences, Astronomical InstituteLynn Wilson III - Goddard Space Flight Center
- Resource Type
- Journal article
- Publication Details
- Space science reviews, Vol.222(7), 75
- DOI
- 10.1007/s11214-026-01328-0
- PMID
- 42840283
- PMCID
- PMC13638725
- NLM abbreviation
- Space Sci Rev
- ISSN
- 0038-6308
- eISSN
- 1572-9672
- Publisher
- Springer Nature
- Grant note
- ANID-FONDECYT: 1260829 Deutsche Forschungsgemeinschaft: 497938371 Science and Technology Facilities Council: ST/W001004/1 National Aeronautics and Space Administration: NNN06AA01C Centro de Astrofsica y Tecnologas Afines: FB210003
J.T.C. acknowledges the financial support provided by the Paris region DIM ORIGINE under grant number IDF-DIM-ORIGINES-2025-2-01. M.E.I. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation), grant number 497938371. D.V. is supported by STFC Consolidated Grant ST/W001004/1. J.S.H. acknowledges support from the Parker Solar Probe (PSP) mission and the Solar Wind Electrons, Alphas, and Protons (SWEAP) team through contract NNN06AA01C. M.R. acknowledges support from the ANID-FONDECYT grant 1260829, as well as from the Center for Astrophysics and Associated Technologies (CATA; ANID Basal grant FB210003).
- Language
- English
- Date published
- 10/05/2026
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9985243572502771
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